The presence of this file enables the "tools_jar_profile" profile in kotlin-annotation-processing, which adds "tools.jar" to the compile dependencies. When Gradle loads this artifact, the "tools_jar_profile" profile should not be activated (cause it adds an extra dependency from the path based on the environment variable). It wouldn't in fact because: 1. This file is normally absent when Gradle build with kapt is launched; 2. Gradle poorly supports Maven profiles.